How to stop theme flash in dark mode toggle
 
       Table of contents         Understanding theme flash problem      Why it happens in Mediumish      Preventing theme flash using CSS      Preventing theme flash using JavaScript      Best practices for smooth theme loading      FAQ       Understanding theme flash problem  The theme flash problem occurs when your site loads with the wrong color scheme for a split second before applying the user's saved preference. In dark mode -enabled sites like Mediumish, this is noticeable: a white background flashes before switching to dark, or vice versa.  While the flash might seem minor, it can disrupt the reading experience, especially for users in dark environments. Reducing or eliminating it helps create a polished, professional feel.   Why it happens in Mediumish  Mediumish loads CSS and JavaScript in sequence. If your theme preference is stored in localStorage  or cookies , JavaScript must read it and then apply a class or data attribute. This happens after  the HTML  is rendered, m...